The invention relates to a method, control system and equipment for preventing the theft of an articulated vehicle and/or a tractor trailer unit.
A drawing vehicle or tractor is traditionally actuated by an ignition lock operated by an ignition key or by a separate start button. Thereafter the hand brake is released from its operable position and driving can be commenced.
One disadvantage connected with the conventional prior art trailers is that anybody can drive or tow a trailer illegally with a properly equipped tractor vehicle. In addition, a tractor-trailer can be seized from the driver by force. Also a vehicle alone or a tractor trailer combination in a parked state can be stolen by so called "hot wiring", i.e., by-passing the ignition lock and starting the motor either from the dashboard or under the hood.
Because the theft rate of vehicles and particularly articulated vehicles has increased, several solutions have been proposed to hamper or prevent such thefts.
Finnish Patent No. 850,958 discloses a device to prevent the theft of a vehicle and a trailer connected with it which includes a brake system operated by pressure medium. The device according to the invention is connected to the before-mentioned break system, and comprises a three-way valve controlled by one code lock and includes one inlet opening and two outlets. The inlet opening to each outlet is controlled by the code lock and thus the pressurization of the break system or vice versa is made possible.
In U.S. Pat. No. 4,436,176 a system to prevent the theft of an articulated vehicle is suggested. Couplings are placed in different parts of the vehicle combination and these couplings must be engaged in a certain order and set to a certain position in order to start the vehicle. The disclosed system functions when connected with the starting circuit of the vehicle.
In British Pat. No. 2,141,567 a device to prevent seizure of a vehicle is also disclosed. The device consists of a code feeding section, a memory section in which a reference code has been deposited in advance, and a comparison section, in which the reference code is compared with the feeding code. The device is coupled to a signal horn and starting system of the vehicle, so that the device, when it is activated by a certain code preventing the seizure, switches off the vehicle motor by the timer section in it after a predetermined time and actuates an alarm signal. If the danger factor is passed, the driver can stop the timer by feeding a certain signal in code form to the device.
German Pat. No. 3,045,345 shows a theft-preventing device influencing the fuel feed or the ignition circuit of the vehicle motor. The device functions by code control, so that a signal in a series of numbers has been predeposited in it and compared with the digital signal to be fed to the device. If the fed signal does not correspond with the deposited signal, the device breaks off the ignition circuit (gasoline motors) or fuel feed (diesel motors) of the vehicle.
Also known is a method used in an anti-theft device sold under the trademark "PSI MKII" by sales agent Pekka Sarssi International Oy Mikonkatu 21 A 00180 Helsinki, Finland. This device is controlled by infra-red beams using a small infra-red transmitter. A disadvantage in the system is its dependence on the driver. Moreover, the infra-red transmitter and the key can be stolen.
In summary the essential disadvantages of previously known anti-theft methods and devices such as code locks, hand break gear locks, alarm arrangements, interlock systems of the steering wheel and pull pin locks are as follows:
the tractor vehicle alone or the tractor trailer combination can be seized after the motor is properly started, PA1 it is relatively easy to defeat the anti-theft devices, PA1 by previously known methods it is not possible with sufficient security to prevent illegal towing or driving of a vehicle combination nor the seizure of a parked tractor or a trailer left by itself. PA1 by locking the turning trailer shaft or bogie to render it as unturnable, or PA1 by locking the trailer, especially half-trailer, as unturnable in regard to the drawing table, PA1 the turning shaft or bogie of the drawing vehicle or the vehicle combination, PA1 the turning joint formed by the pull pin and the drawing table, PA1 the turning pull pin moved in a position, in which its connection to the drawing table is prevented.
Connected with the above-mentioned, one must still particularly emphasize, that trailers left by themselves are usually entirely devoid of any seizure-preventing devices and thus quite suitable objects for capture.
The first goal of the present invention is to achieve a solution based on a completely novel way of thinking to prevent the seizure of vehicles and trailers. The rapid breaking or evading of such solution is not possible and by which the thefts of both a trailer left by itself and a tractor trailer combination are reliably prevented. The second goal of the invention is to eliminate the disadvantages and weaknesses in the previously known methods and devices for prevention of seizures and to thus prevent thefts of trailers and articulated vehicles during both driving and parking.
These goals have been achieved by the method, control system and equipment according to the invention, the characteristic features of which have been described in the appended claims.